The Lamellar Cells of Vertebrate Meissner and Pacinian Corpuscles: Development, Characterization, and Functions.

Teresa Cobo,José A Vega,Jorge García-Piqueras,Olivia García-Suárez,Yolanda García-Mesa,Iván Suazo

doi:10.3389/fnins.2022.790130

Teresa Cobo, José A Vega + Show 4 more

Open Access

https://doi.org/10.3389/fnins.2022.790130

Copy DOI

Abstract

Sensory corpuscles, or cutaneous end-organ complexes, are complex structures localized at the periphery of Aβ-axon terminals from primary sensory neurons that primarily work as low-threshold mechanoreceptors. Structurally, they consist, in addition to the axons, of non-myelinating Schwann-like cells (terminal glial cells) and endoneurial- and perineurial-related cells. The terminal glial cells are the so-called lamellar cells in Meissner and Pacinian corpuscles. Lamellar cells are variably arranged in sensory corpuscles as a “coin stack” in the Meissner corpuscles or as an “onion bulb” in the Pacinian ones. Nevertheless, the origin and protein profile of the lamellar cells in both morphotypes of sensory corpuscles is quite similar, although it differs in the expression of mechano-gated ion channels as well as in the composition of the extracellular matrix between the cells. The lamellar cells have been regarded as supportive cells playing a passive role in the process of genesis of the action potential, i.e., the mechanotransduction process. However, they express ion channels related to the mechano–electric transduction and show a synapse-like mechanism that suggest neurotransmission at the genesis of the electrical action potential. This review updates the current knowledge about the embryonic origin, development modifications, spatial arrangement, ultrastructural characteristics, and protein profile of the lamellar cells of cutaneous end-organ complexes focusing on Meissner and Pacinian morphotypes.

Highlights

A subset of peripheral axon terminals from primary sensory nerve fibers reaches the vertebrate dermis and contacts with distinct differentiated cells to form microscopic sensory organs referred to as sensory corpuscles (Zimmerman et al, 2014; Cobo et al, 2021)
cutaneous end-organ complexes (CEOCs) are continuous with nerve fibers whose axons originate from intermediate- or large-sized mechanosensory neurons that work as low threshold mechanoreceptors (LTMRs) [see for a review (Abraira and Ginty, 2013)]
A recent research has identified proteins essential for mechanotransduction and some others that can be required for some events of the mechanotransduction. Most of these proteins are related to ion channels (Martinac and Poole, 2018; Douguet and Honoré, 2019; Jin et al, 2020; Kefauver et al, 2020). Both voltage-gated and voltage-independent ion channels have been proposed to initiate mechanotransduction, and all have been localized in Meissner and/or Pacinian corpuscles primarily in the membrane of the axon and in the terminal glial cells

Summary

Introduction

A subset of peripheral axon terminals from primary sensory nerve fibers reaches the vertebrate dermis and contacts with distinct differentiated cells to form microscopic sensory organs referred to as sensory corpuscles (Zimmerman et al, 2014; Cobo et al, 2021). We review and update the embryonic origin, development, morphology, ultrastructure, immunohistochemical profile, and putative functions of the terminal glial cells within the CEOCs, especially Meissner and Pacinian corpuscles.

Results

Conclusion